Scanning electron microscopy of Treponema pallidum (Nichols strain) attached to cultured mammalian cells

Abstract

This paper describes the attachment of Treponema pallidum (Nichols strain) to cultured mammalian cells as a visualized by scanning electron microscopy. Treponemes were incubated for 3 hr with cultured cells derived from normal rabbit testes or human skin epithelium, then fixed, processed with critical-point drying, and examined with a Cambridge Mark 2A scanning electron microscope. Large numbers of treponemes became attached to the cultured cells without altering the morphological integrity of the cultured cells. Attachment appeared to involve a very close physical proximity of treponemes to the cultured cells; at the site of attachment, no changes such as swelling or indentation of the cultured cell surface were observed. The addition of ruthenium red to the fixatives produced a treponemal-associated surface precipitate. This material, which is probably mucopolysaccharide and/or phospholipid, may be important in protecting the organisms against host defense mechanisms; in addition, it may be involved in the serological unresponsiveness of freshly prepared suspensions of T. pallidum.

Scanning electron microscopy of the adhesion of Treponema pallidum subspecies pallidum (Nichol strain) to human brain microvascular endothelial cells in vitro

“…It has been reported that T. pallidum could attach to a series of cultured cells derived from human and other mammals. 7,9 Similar to previous studies, the attachment of treponemes did not alter the morphological integrity of HBMECs. The difference is that our results showed that attached treponemes were concentrated on certain areas of cell surface rather than evenly distributed on the cell surface.…”

“…Fitzgerald et al thought that attachment of treponemes to cultured cells appeared at a very close physical proximity. 9 However, our results showed that treponemes seemed to have merged with HBMECs at the attachment point with tips. T. pallidum was found to exist in the intercellular junctions of endothelial monolayer and was able to make its way below the monolayer.…”

Electron microscopy of Treponema pallidum (Nichols) cultivated in tissue cultures of Sf1Ep cells

“…Numerous reports (7, 8, 14-16, 18, 19, 21) have described the interaction of T. pallidum and tissue cells and the nature of attachment as determined by electron microscopy. Fitzgerald et al (8) and Repesh et al (21) reported that T. pallidum caused no morphological changes of tissue culture cells. However, in further studies, Fitzgerald et al (15) and Oakes et al (18) described various degrees of the cultured cell disruption caused by coincubation with T. pallidum.…”

Quantitative Assessment of Bacterial Adhesion to Eukaryotic Cells of Human Origin

“…THE ADHESION OF bacteria to eukaryotic cell surfaces has been studied extensively (McNeish et al 1975;Fitzgerald et al 1977) and various methods of quantitation used. McNeish, for example, determined the number of bacteria adhering to the eukaryotic cells by blending the preparation and then counting the number of micro-organisms present by conventional bacteriological tests.…”